DESCRIPTION: The objective of this proposal is to identify the cis-acting signals involved in the replication and assembly of vesicular stomatitis virus (VSV). Two novel reverse genetic systems that allow directed manipulation of the VSV genome will be used to test several hypotheses proposed previously for how VSV replicates within host cells. The requirements for the assembly and release of VSV virions at the cell surface will also be examined. The first specific aim will examine the role of conserved sequences found at the 5' end of each VSV gene in gene expression. The second specific aim will examine the importance of an AU-rich sequence found at the 3' end of upstream genes on the expression of adjacent downstream genes. The third specific aim will examine sequences at the 5' end of the genomic RNA of VSV that are thought to contain a specific encapsidation signal required for nucleocapsid formation. The fourth specific aim will examine the effects of mutations in the G protein cytoplasmic domain on virus assembly and virus infectivity.